fix: reuse Azure and Oracle clients across requests; document DI lifetime audit

[mmalkhatib]

Summary

Follow-up to #70 (S3 client-lifetime fix, live prod incident). Audited the other three network-backed providers for the same class of bug — building a fresh SDK client on every DI resolution instead of reusing a pooled, thread-safe one.

• Azure (SW.CloudFiles.AS): same AddTransient bug as S3, and worse. The DI extension registered a singleton BlobContainerClient that was never actually used — CloudFilesService's constructor built its own client via a field initializer instead of taking one as a parameter. In the non-managed-identity auth path, that means a synchronous, blocking GetBlobContainers() list call on every single construction, not just a fresh handshake. Fixed: CloudFilesService now takes BlobContainerClient via constructor injection (reusing the registered singleton), ICloudFilesService is now AddSingleton.
• Oracle (SW.CloudFiles.OC): was AddScoped — milder than Transient, but still built a fresh ObjectStorageClient + UploadManager (plus a disk read of the PEM/config file) once per HTTP request. Changed to AddSingleton.
• Google Cloud (SW.CloudFiles.GC): already correct — ICloudFilesService is AddScoped, but the real StorageClient/UrlSigner are AddSingleton and injected, so no repeated client construction regardless. No change.

Also documents the full audit in CLAUDE.md and adds client-reuse/timeout notes to README.md.

None of Azure/GCS/Oracle are used by any Traxis service today (only S3 is) — this is library-quality debt, not a live incident.

Test plan

• dotnet build clean across the whole solution
• SW.CloudFiles.AS.UnitTest / SW.CloudFiles.OC.UnitTest fail identically with and without this change (confirmed by reverting and re-running) — pre-existing, need live cloud credentials, consistent with CI's run-tests: 'false'

🤖 Generated with Claude Code

[coderabbitai]

Important

• 🔍 Trigger review

This repository does not receive automatic reviews because it has fewer than 10 stars.

⚙️ Run configuration

Configuration used: Repository: simplify9/coderabbit/.coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 65707533-8981-4d21-9907-7f9b4eae4c9b

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}